BEIJING, Aug. 11 (Xinhua) -- More world records tumbled in the pool in a stunning way, Michael Phelps stayed on course for a record eight gold medals while first doping case surfaced on Monday at the Beijing Olympics.

　　Kosuke Kitajima of Japan successfully retained his 100m breaststroke title in a world record time of 58.91 seconds, shaving 0.22 off the previous world best set by American Brendan Hansen in 2006.

　　"It feels even better than Athens. It's wonderful to be able to savor a moment like this again. I have been waiting so long for it," said Kitajima, the first Japanese swimmer to win three individual Olympic medals.

　　Zimbabwe's Kirsty Coventry chopped two tenths of a second off the 100m backstroke record to win her semifinal heat in 58.77 seconds.

　　Thanks to U.S. teammate Jason Lezak's heroic performance in the men's 4x100m freestyle relay final, Phelps won the second of what he hopes will be a record eight gold medals.

　　Lezak, the anchor of the American quartet, was nearly a body length behind French leader Alain Bernard at the final turn, but the 32-year-old charged to overtake his rival finally, but just by centimeters. The U.S. team's result of 3:08.24 was 3.99 seconds off the world record they set earlier in the heats.

　　"It was unbelieveable. Jason finished the race better than we could have asked for," Phelps said. "At the end, as you could see I was pretty excited. I lost my voice, and I was very emotional."

　　Phelps will go for his third gold in Tuesday's 200m freestyle.

　　In the morning session's other finals, Australian Lisbeth Trickett won the women's 100m butterfly in 56.73, while the women's 400m freestyle gold went to Britain's Rebecca Adlington in 4:03.22.

　　Spanish cyclist Maria Isobel Moreno became the first cheat caught by strict doping control at the Beijing Games. The 27-year-old tested positive for EPO, a blood-boosting hormone, and left China on July 31, the day before the result was informed.

　　Moreno faces a two-year ban and, under the IOC's new rule, she could be barred from the 2012 London Olympics.

　　Chinese teenagers Lin Yue and Huo Liang led all the way to win the men's 10-meter platform synchronized event with 468.18 points, the host nation's second gold in diving in two days.

　　Chen Yanqing won the eighth gold for China at the Beijing Games as she scored a comfortable victory in the women's 58kg class weightlifting. The 29-year-old, who came out of retirement to represent her country at the Games, hoisted 106kg in snatch and 138kg in clean and jerk to become the first woman to win back-to-back Olympic gold in weightlifting.

　　"I think it's the best way to end my weightlifting career with an Olympic gold," said Chen. "It's a one-in-a-million chance for me to compete in the Olympics hosted by my country, and though I've encountered many difficulties, I survived. This couldn't be a better result for me."

　　India, the world's second most populous country after China, won its first ever Olympic shooting gold medal when Abhinav Bindra detrhoned Chinese defending champion Zhu Qinan to win the men's 10m air rifle title.

　　Bindra, who trailed by two points after the qualification round, went into the last shot in the final level with Henri Hakkinen of Finland on 689.7 points. While Bindra scored 10.8 in the deciding shot, Hakkinen tallied only 9.7 to concede the silver to Zhu.

　　"It's the best feeling of my life. It's hard to describe," said Bindra, a 25-year-old businessman.

　　Satu Makela-Nummela grabbed Finland's first gold medal at the Games when she won the women's trap event.

　　Japanese shuttlers Miyuki Maeda and Satoko Suetsuna pulled off a major upset in badminton when they came from one set down to beat Chinese reigning Olympic champions Yang Wei and Zhang Jiewen 8-21, 23-21, 21-14 in the quarterfinals of the women's doubles.

　　"This was the biggest win of our lives," Suetsuna said.